Hydraulic Fluid and Lubricant Compositions Using Biodiesel

ABSTRACT

A composition and method of making hydraulic fluids and lubricants using biodiesel as a blending component or base oil. Preferably around 0.1 to 45% of biodiesel is used as a blending component in a hydraulic fluid or as a base oil or additive in a lubricant. The use of biodiesel has environmental and cost advantages over other blending components or base oils. Lubricants and hydraulic fluids having ISO viscosity grades as low as 22 and 32 may be achieved by the use of biodiesel, while still meeting applicable standards for environmental acceptability.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. provisional patent application No. 62/260,907 filed Nov. 30, 2015.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the use of biodiesel as a blending component to achieve environmentally acceptable hydraulic fluids or lubricants, particularly those having ISO viscosity grades of 46 or lower.

2. Description of Related Art

During recent years, there has been an increasing interest in various hydraulic fluids and lubricants that have little or no long-term impact on the environment. In some hydraulic fluid and lubricant applications, such as hydraulic fracturing (or “fracking”) and marine applications (including vessels that operate on oceans, lakes, and rivers) the hydraulic fluid or lubricant may enter the environment during normal use, which may result in a negative environmental impact. Some hydraulic fluids and lubricants use biodegradable and non-toxic ingredients to be more “environmentally friendly.” In recent years, standards have been developed to define what constitutes an “environmentally friendly,” “environmentally acceptable,” and “environmentally considerate” hydraulic fluid or lubricant. For example, several European specifications defining environmentally acceptable lubricants have been developed including Blue Angel, Nordic Swan, and Swedish Standards SS 155434 and 155470. While these specifications differ in the details of their test requirements, they recognize three important properties that are needed for a lubricant to be environmentally acceptable: sufficient biodegradability, minimal aquatic non-toxicity, and non-bioaccumulation.

Another European specification, the European Ecolabel takes a somewhat different approach. Instead of only providing specific recognized laboratory tests to demonstrate acceptability in the three aforementioned properties, a list of acceptable components is provided, including both base oils and performance additives. This list is known as the Lubricant Substance Classification List (LuSC list). As long as the lubricant formulation consists of only components from that list, and as long as each component does not exceed any maximum percentage specified on the list, then the formulation can be deemed environmentally acceptable under the European Ecolabel specification.

Within the U.S., the Environmental Protection Agency (EPA) issued the Vessel General Permit (VGP) document on Dec. 19, 2013. This document defines what it means for a lubricant to be environmentally acceptable for use within U.S. waters. The VPG bases its requirements on the same three properties previously mentioned and provides recognized test methods for each that can be used to demonstrate acceptable performance for any lubricant formulation under consideration. However, the VGP also allows for the approval of a lubricant formulation by one of the other recognized specifications. If a lubricant formulation gains approval by one of the other specifications, then by default it will be deemed acceptable by the VGP specification.

In order to make a hydraulic fluid or lubricant more environmentally friendly to meet the various standards in Europe and the U.S., biodegradable and non-toxic base oils, such as vegetable oils or synthetic esters, are typically used. However, such base oils and blending components may result in higher than ideal viscosities for the hydraulic fluid or lubricant. Depending on the application, hydraulic fluids and lubricants can be required to have a range of viscosities as defined by the ISO viscosity grade system. In this system, the ISO viscosity grade is defined by the kinematic viscosity at 40 C as measured by ASTM D445. Defined ISO viscosity grades include 2, 3, 5, 7, 10, 15, 22, 32, 46, 68, 100, 150, 220, 320, 460, 680, 1000, and 1500. A fluid is considered within a given ISO viscosity grade if its kinematic viscosity at 40 C is within +/−10% of the grade number. That is, a fluid is a grade 46 fluid if its viscosity is within +/−10% of 46 cSt at 40 C. Fluid lubricant applications rarely require a viscosity grade lower than ISO 22 and are more typically in the range of ISO 22, 32, or 46, although some are 68 and higher.

The most common base oils used for environmentally acceptable lubricants (“EAL”) are vegetable (plant-based) oils, since these will typically be highly biodegradable, acceptably non-toxic, and essentially non-bioaccumulative. Any of the commonly available vegetable oils should typically be suitable if sufficiently evaluated. Many have already been verified as acceptable, and some of them are already on the LuSC list. Animal-based fatty oils such as beef tallow can also be used, but such oils are less available. Also, many such fatty oils are solids at 25 C and are consequently less attractive as a base oil choice.

Some synthetic base oils also meet the requirements for an EAL, and can also be used. One important class of such synthetic base oils includes certain synthetic esters. These synthetic esters are available from multiple sources. However, they will typically be much more costly than vegetable oils. Another class of synthetic base oils that could meet the requirements for an EAL includes certain oil-soluble polyalkylene glycols. However, like the synthetic esters, they will typically be significantly more costly than vegetable oils.

Blown vegetable oils may also be used when higher ISO viscosity grades are required. Blown vegetable oils are made by the controlled partial oxidation of a vegetable oil, resulting in a product that contains vegetable oil-based polymers with higher viscosity than the parent oil. Likewise, certain high viscosity oil-soluble polymers can be used to boost viscosity, when desired. When such polymers are used, they may be thought of as either an additive or as a high viscosity base oil component added at lower levels. Table 1 provides. Kinematic Viscosity data for some vegetable oils that may be used as base oils in environmentally friendly hydraulic fluids and lubricants.

TABLE 1 Viscosity Data (cSt) for Vegetable Oils Temp Temp Temp Temp Oil Variety or Processing 20 C. 23.9 C. 25 C. 27 C. Rapeseed 76 Canola Refined, bleached, 63 deodorized Canola Refined, bleached, 65 winterized Soybean 55 Peanut 73 Cottonseed 60 Palm 89 Rapeseed 75 Corn 46 Cottonseed 50 Palm Poppy 56 Rapeseed 40 Rapeseed Soybean 65 Sunflower 58 Cottonseed Crude 76 Cottonseed Refined 70 Cottonseed Refined, bleached, and 75 deodorized Peanut Crude 80 Peanut Refined 82 Peanut Refined, bleached, and 83 deodorized Soybean Crude 66 Soybean Degummed 66 Soybean Refined 64 Soybean Hydrogenated Sunflower Crude 66 Sunflower Refined 65 Sunflower Dewaxed 65 Sunflower Refined, bleached, and 67 deodorized Crambe 96 Rapeseed 87 Corn 57 Soybean 59 Milkweed 61 Coconut Lesquerella 293

This viscosity data is based on temperatures in the 20 C-27 C range. In the 40 C range (used for ISO viscosity grades), the viscosities of these oils will be substantially lower than 46 cSt needed for ISO viscosity grade 46 and substantially higher than 22 cSt needed for ISO viscosity grade 22. The viscosity can be modified, to increase or decrease it as desired, by blending in higher or lower viscosity components. When an ISO viscosity grade of 46 or higher is desired, these base oils can be blended with sufficient amounts of other higher viscosity components, such as synthetic base oils (or synthetic esters), blown vegetable oils, and high viscosity polymers to achieve a higher viscosity hydraulic fluid or lubricant that still meets the environmental acceptability standards because many of the prior art higher viscosity blending components meet those standards. However, when an ISO viscosity grade lower than 46 is desired, it is difficult to achieve the desired lower viscosity and meet the environmental acceptability standards. This is because prior art lower viscosity blending components, such as low viscosity mineral oils or synthetic hydrocarbons such as polyalphaolefins, do not provide the desired level of biodegradability, so the resulting hydraulic fluid or lubricant will not meet the environmental acceptability standards. Furthermore, such non-biodegradable blending components/base oils are not included in the LuSC list. Further complicating the situation is the fact that the performance additives used in hydraulic fluids will generally be much more viscous than any of the base oil components, thereby driving the viscosity of the complete formulated product even higher.

There is a need for a fully biodegradable and very low viscosity blending component that can be used, most desirably at lower concentrations, to achieve lower ISO viscosity grades (including the lowest commonly used grades of 32 and 22) by blending them into the normally used, higher viscosity base oils to achieve a lubricant or hydraulic fluid that meets the applicable standards to be considered environmental friendly or acceptable. Additionally, there is a need for such a blending component that is not excessively volatile and that has an acceptably high flash point.

Biodiesel has become established as an alternative diesel fuel blending component, but has not been previously used as a low viscosity blending component for hydraulic fluids or lubricants. Biodiesel is composed of the alkyl mono-esters (usually methyl mono-esters) of fatty acids derived from various plant and animal fatty oils. The most common fatty oil sources used to make biodiesel in the U.S. are soybean oil and used cooking oil. When biodiesel is made from soybean oil, it is sometimes called methyl soyate. In Europe, rapeseed oil is commonly used. In the Asian Pacific Rim area, palm and coconut oil are also used.

The most common method to make biodiesel is to trans-esterify the fatty oil with a stoichiometric excess of methanol in the presence of an aqueous strong base catalyst such as sodium hydroxide or potassium hydroxide. After the reaction is complete, the excess methanol, water, glycerol byproduct, and base are removed by aqueous washing. The final biodiesel can optionally be further purified by methods similar to those used to purify vegetable oils, such as distillation. ASTM D6751 governs the quality of pure biodiesel, also known as B100, as a diesel fuel blending component not to exceed 20% of the total diesel fuel. According to this specification, the kinematic viscosity at 40 C cannot exceed 4.01 cSt and the flash point cannot be lower than 93 C (199 F). Since biodiesel has all the chemical structural features of the fatty oil from which it was made except for the glycerol backbone, it should have essentially the same if not greater biodegradability as its parent source. Thus, biodiesel as currently manufactured appears to have the bulk properties required to be a hydraulic fluid or lubricant blending component for lower ISO viscosity grades that are not achievable by the currently used biodegradable base oils and allows the resulting hydraulic fluid or lubricant to meet applicable environmental acceptability standards.

SUMMARY OF THE INVENTION

According to one preferred embodiment of the invention, biodiesel is blended with one or more other base oils to form a hydraulic fluid or other lubricant with a lower ISO viscosity grade. According to another preferred embodiment, the one or more other base oils blended with biodiesel comprise one or more vegetable or plant oils. According to yet another preferred embodiment, the one or more other base oils comprise synthetic base oils (including synthetic esters or oil-soluble polyalkylene glycols), used alone (biodiesel blended only with synthetic base oil(s)) or in combination with one or more vegetable or plant oils. According to yet another preferred embodiment, the one or more other base oils are only vegetable or plant oils and no synthetic base oils are used. Because the synthetic base oils are typically higher viscosity than vegetable or plant oils, the use of a synthetic base oil as part of the hydraulic fluid or lubricant composition will usually require more biodiesel to offset the increase in viscosity caused by the inclusion of the higher viscosity base oil than would be required if only vegetable or plant oils are used as the other base oils. The inclusion of synthetic base oils and increased amount of biodiesel may be more costly, but may be particularly useful in some applications such as applications where extremely wet conditions or higher operating temperatures exist. Also, there is sometimes a marketing advantage for an environmentally acceptable lubricant that is partially or fully synthetic. Other suitable base oils for blending with biodiesel according to various embodiments of the invention include blown vegetable oils, animal based fatty oils, high viscosity polymers, and any other environmentally acceptable base oil as would be known to anyone with ordinary skill in the art, which may be used alone or in any combination with any other base oil referenced herein.

According to another preferred embodiment, blending biodiesel with one or more other base oils results in a hydraulic fluid or other lubricant that meets one or more standards or specifications for environmental acceptability. According to another preferred embodiment, blending biodiesel with one or more other base oils results in a hydraulic fluid or other lubricant that has an ISO viscosity grade of 22, 32, or 46. According to another preferred embodiment, blending biodiesel with one or more other base oils results in a hydraulic fluid or other lubricant that has a Viscosity Index greater than around 200, particularly when the hydraulic fluid or lubricant is an ISO 22 or 32 viscosity grade. According to another preferred embodiment, biodiesel comprises around 0.1 to 55% of the hydraulic fluid or lubricant by weight. More preferably, the biodiesel comprises around 1% to 30%, most preferably 5% to 26%, by weight of the hydraulic fluid or lubricant. When biodiesel is blended only with synthetic base oil(s) (no vegetable or plant oil, but other additives may optionally be used as desired) to form a lower ISO viscosity grade 22 or 32 hydraulic fluid or lubricant, preferably the biodiesel comprises around 5 to 55% of the hydraulic fluid or lubricant by weight. When biodiesel is blended only with vegetable or plant oil(s) (no synthetic base oils, but other additives may optionally be used as desired), to form a lower ISO viscosity grade 22 or 32 hydraulic fluid or lubricant, preferably the biodiesel comprises around 5 to 35% of the hydraulic fluid or lubricant by weight. The use of biodiesel as a blending component will allow low viscosity grades of hydraulic fluids or lubricants to be achieved while maintaining the desirable environmentally acceptable properties of biodegradability that would otherwise be lost when more commonly used low viscosity base oils are used as blending components. The use of biodiesel also has the advantage of lower costs. The use of biodiesel also aids in the efficient transfer of hydraulic power in hydraulic equipment when the hydraulic fluid comprises biodiesel.

According to another preferred embodiment of the invention, biodiesel is blended with one or more other base oils to form a hydraulic fluid or other lubricant with a higher ISO viscosity grade. According to this embodiment, the one or more other base oils preferably comprise at least one higher viscosity base oil, such as a synthetic base oil (synthetic ester), blown vegetable oil, or high viscosity polymers, preferably with a viscosity at 40 C in the ISO range of 46 or 68 or higher. A lower viscosity vegetable or plant oil (or a lower viscosity synthetic base oil, such as Priolube 3970) may also be used with a higher viscosity base oil, or the higher viscosity base oil(s) may be the only other base oil used without any lower viscosity vegetable or plant oil. According this embodiment, blending biodiesel with one or more other base oils including at least one higher viscosity base oil results in a hydraulic fluid or other lubricant that has an ISO viscosity grade preferably higher than 46 and that meets one or more standards or specifications for environmental acceptability. Most preferably, biodiesel comprises around 1 to 10% of the higher viscosity hydraulic fluid or lubricant by weight. Other amounts of biodiesel may also be used depending on the viscosity of the higher viscosity base oil used and the targeted ISO viscosity grade desired.

Hydraulic fluids and lubricants comprising biodiesel according to the various embodiments of the invention may also comprise one or more performance additives, that are well known in the art. Such additives include but are not limited to extreme pressure additives, anti-wear additives, rust inhibitors, corrosion inhibitors, demulsifiers, emulsifiers, metal deactivators, copper passivators, rheology modifiers, oxidation inhibitors, anti-foam additives, anti-leak compounds, chemical markers, chelating agents, dyes, and fragrance imparters. Most preferably, any performance additives will not adversely impact the environmental acceptability of the hydraulic fluid or lubricant according to applicable standards or specifications.

The use of biodiesel as a blending component with other base oils according to the various embodiments of the invention provides several advantages over the use of known prior art blending components. For example, it is possible to achieve environmentally acceptable hydraulic fluids and lubricants with lower ISO viscosity grades (ISO 32, 22, and lower) that are not typically attainable with prior art environmentally acceptable base oils. It is also possible to achieve hydraulic fluids and lubricants with higher ISO viscosity grades (ISO 46 and higher) by using less than what would otherwise be required of the lower viscosity environmentally acceptable base oil when the hydraulic fluid was originally formulated with a blend of a lower and a higher viscosity base oil. It is also possible to achieve improved (increased) viscosity index, especially at the lower ISO viscosity grades where improvement in this property is most needed. According to preferred embodiments of the invention, biodiesel may be used as a blending component in any fluid lubricant application where there is an advantage to using a fatty oil or other higher viscosity biodegradable oil as a base oil. Likewise, biodiesel may be used in lubricating greases where similar demands on the base oil are present.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A hydraulic fluid according to one preferred embodiment of the invention comprises: B100, one or more vegetable oils, and one or more higher viscosity base oils (synthetic base oils, such as a synthetic ester, or blown vegetable oils, or high viscosity polymers, or a combination thereof). Preferably, the hydraulic fluid according to this embodiment has an ISO viscosity grade of 32 or 22, but may also include grades higher than ISO 32, depending on how much higher viscosity base oil (synthetic base oil, blown vegetable oil, or high viscosity polymer) is used. Preferably, the hydraulic fluid according to this embodiment comprises 0.1% to 45% B100, 89% to 53% total vegetable oil, and 10% to 0.1% total higher viscosity base oil. More preferably the hydraulic fluid according to this embodiment comprises 1% to 30% B100, 90% to 69% total vegetable oil, and 8% to 0.5% total higher viscosity base oil. Most preferably the hydraulic fluid comprises 5% to 26% B100, 95% to 73% total vegetable oil, and 6% to 1% total higher viscosity base oil. Other amounts may also be used, depending on the viscosity of the vegetable and higher viscosity base oil(s) used and the targeted ISO viscosity grade, as will be understood by those of ordinary skill in the art.

A hydraulic fluid according to another preferred embodiment of the invention comprises: one or more vegetable or plant oils and B100, without any separately added synthetic base oil component (such as a synthetic ester), blown vegetable oil, or high viscosity polymer. Preferably, the hydraulic fluid according to this embodiment has an ISO viscosity grade of 32 or 22 (or any viscosity at 40 C between those grades). Preferably, the hydraulic fluid according to this embodiment comprises 0.1% to 45% by weight B100 and 99.9 to 55% vegetable oil (total, if more than one vegetable oil is used), more preferably 1% to 40% B100 and 99% to 60% total vegetable oil, and most preferably 5% to 35% B100 and 95% to 65% total vegetable oil. Other amounts may also be used, depending on the viscosity of the vegetable base oil(s) used and the targeted ISO viscosity grade, as will be understood by those of ordinary skill in the art.

A hydraulic fluid according to another preferred embodiment of the invention comprises: one or more higher viscosity base oils (synthetic base oils, such as a synthetic ester, or blown vegetable oils, or high viscosity polymers, or a combination thereof) and B100, without any separately added vegetable oil. Preferably, the hydraulic fluid according to this embodiment has an ISO viscosity grade of 32 or 22, but may also include grades higher than ISO 32, depending on how much higher viscosity base oil (synthetic base oil, blown vegetable oil, or high viscosity polymer) is used. Preferably, the hydraulic fluid according to this embodiment comprises 0.1% to 55% by weight B100 and 99.9 to 45% total high viscosity base oil, more preferably 1% to 45% B100 and 99% to 55% total high viscosity base oil, and most preferably 5% to 40% B100 and 95% to 60% total high viscosity base oil. Other amounts may also be used, depending on the viscosity of the higher viscosity base oil(s) used and the targeted ISO viscosity grade, as will be understood by those of ordinary skill in the art.

Performance additives may optionally be included in any of the composition embodiments according to the invention and, if present, will be present in total amount preferably between 0.1% to 15%, more preferably 1% to 10%, and most preferably 2% to 7% by weight of the hydraulic fluid. Most preferably any performance additives qualify as environmentally acceptable by one or more of the prevailing specifications, as previously described.

Blending of the hydraulic fluids of any embodiment of this invention may be accomplished by any of the known blending methods used for any of the prior art hydraulic fluids or other fluid lubricants and using any of the available blending equipment, as will be understood by those of ordinary skill in the art. The order of addition of the components during the blending process is not critical. Likewise, the temperature at which the blend is to be heated during mixing is not important as long as safety considerations concerning the flash point of the components and final product are observed. The blending duration can be any value that provides a homogenous final product, as will be understood by those of ordinary skill in the art.

The hydraulic fluid and lubricant compositions and methods for making such compositions according to the invention are further described and explained in relation to the following experimental examples. All blends were made by blending the components in glass beakers using either magnetic stirring bars on stirring plates or with a propeller mixing device. Blending temperatures were 100 F to 120 F. Blends were tested for Kinematic Viscosity at 40 C and at 100 C according to ASTM D445. Viscosity Index (“VI”) was determined according to ASTM D2270. For a few representative blends, Cloud Point was determined according to ASTM D5773, Pour Point was determined according to ASTM D5949, and Four Ball Wear scar diameter was determined according to ASTM D4172. These test results are not critical to the scope of this invention, but are provided to show some performance attributes imparted by performance additives used in those example blends. Supplier and viscosity information on the components used for all example blends, which are representative of components suitable for use in EAL hydraulic fluids according to preferred embodiments of the invention, are provided below in Table 2. The compositions according to the invention are not limited to the other base oils and performance additives identified in Table 2, and other suitable base oils and additives may also be used according to the invention.

TABLE 2 Viscosity Data for Typical Components Suitable for Use in EAL Hydraulic Oils According to Preferred Embodiments of the Invention Component Component Component Component Viscosity, Viscosity, Name Description Supplier cSt @ 40 C. cSt @ 100 C. B100 Biodiesel Archer Daniels 4.07 (methyl soyate) Midland Co.; Renewable Energy Group, LLC Agri-Pure Vegetable Oil Cargill, Inc 38 85 Agri-Pure Trimethylolpropane Cargill, Inc 48 456 trioleate (Synthetic Ester that has a vegetable oil structure) Priolube Synthetic Ester Croda, Inc. 67 1445 Priolube Synthetic Ester Croda, Inc. 20 3970 Priolube Synthetic Ester Croda, Inc. 145 3987 Viscoplex Polymeric pour Evonik Industries 1800 10-310 point depressant Additin M Hydraulic oil RheinChemie 280 93.001 performance Rheinau GmbH additive Functional High molecular Functional 6500-7500 V-508F weight polymer Polymers, Inc.

All of these components are suitable for use in environmentally acceptable hydraulic fluids by one or more of the prevailing specifications. It should be noted that Agri-Pure 456 is a very specific synthetic ester that has the structure of a vegetable oil where all three esterically bonded fatty acids are oleic acid, and where an ethyl group is attached to the C2 carbon of the glycerol backbone. As such it can be considered to be a polyol ester that resembles a chemically modified vegetable oil both in its chemical structure and viscosity. Priolube 1445 and Priolube 3970 are polyol esters. Priolube 3987 is a higher viscosity synthetic ester. The Table 2 viscosity data show the same thing that was shown in the Table 1 viscosity data: when making a hydraulic oil using such vegetable oil base oils and performance additives, a viscosity grade below ISO 46 will not be possible unless a low viscosity, environmentally acceptable base oil such as B100 is also used.

Four blends were prepared as Examples 1-4, using vegetable oil, without any higher viscosity synthetic ester base oil, and with or without biodiesel. The compositions and test data for those blends were provided below in Table 3.

TABLE 3 B100 Used in Lower Grade Hydraulic Fluid Blends Containing Vegetable Oil with Synthetic Ester Base Oil Example Number 1 2 3 4 %(wt) B100 (REG) 25.26 10.30 0.00 0.00 Agri-Pure 85 71.20 86.18 42.34 0.00 Agri-Pure 456 0.00 0.00 54.14 94.99 Priolube 1445 0.00 0.00 0.00 0.00 Priolube 3970 0.00 0.00 0.00 0.00 Priolube 3987 0.00 0.00 0.00 0.00 Viscoplex 10-310 0.51 0.59 0.52 0.25 Additin M 93.001 3.03 2.93 3.00 3.03 Functional V-508F 0.00 0.00 0.00 1.73 Total 100.00 100.00 100.00 100.00 Target ISO Viscosity Grade 22 32 46 68 Kinematic Viscosity @ 40° C., 22.15 32.31 43.49 53.09 cSt Kinematic Viscosity @ 100° C., 5.72 7.45 8.89 10.52 cSt Viscosity Index 221 209 190 193

In these four Examples, as in all the subsequent examples, the hydraulic fluid performance additive, Additin M 93.001, and the pour point depressant, Viscoplex 10-310, are used at concentrations known to provide acceptable performance in vegetable and synthetic ester base oils. Also, unless otherwise specified, all compositional percentage values are based on the total weight of the hydraulic fluid blend. As can be seen, these four example blends were targeted to achieve ISO viscosity grades of 22, 32, 46, and 68. The two lowest viscosity grades (Examples 1 and 2) were successfully achieved by using B100 as a low viscosity blending component with the vegetable oil Agri-Pure 85. The ISO 46 grade product (Example 3) did not need B100, but was successfully made by blending a combination of the two vegetable oil-based base oils Agri-Pure 85 and Agri-Pure 456.

It should be noted that the VI of Examples 1 and 2 were significantly higher than Examples 3 and 4. VI is a relative indicator of how much the viscosity of a fluid decreases as the temperature increases. Higher VI values indicate less reduction of viscosity with increasing temperature, which is desirable for hydraulic fluids, and this is especially true with lower viscosity grades where the viscosity is low to begin with. By comparing the compositions of Examples 1-4, it appears the unexpected higher VI benefit achieved with Examples 1 and 2 is the result of the inclusion of biodiesel in those compositions. Thus, not only did the inclusion of B100 as a blending component or base oil allow successful achievement of the ISO 22 and 32 viscosity grades, it also improved (increased) the VI of those hydraulic fluid blends compared to the targeted ISO 46 and 68 hydraulic oil blends where B100 was not used.

Example 4 was targeted to meet the ISO 68 viscosity grade. However, as can be seen, even though the somewhat more viscous Agri-Pure 456 was used, the blend was not sufficiently viscous to achieve the ISO 68 grade. As such, it appears that inclusion of at least one a higher viscosity component, such a higher viscosity synthetic ester and/or a high viscosity polymer, is required to achieve viscosity grades higher than ISO 46.

The next four hydraulic fluid blends, Examples 5-8, were prepared to demonstrate how incorporation of a small amount of a synthetic ester base oil can be used when making hydraulic fluids with viscosity grades targeted at ISO 22, 32, 46, and 68. The composition and test data for these blends are provided in Table 4 below:

TABLE 4 B100 Blends in Lower Viscosity Grade Hydraulic Fluid Blends Containing Vegetable Oil and Synthetic Ester Base Oil Example Number 5 6 7 8 %(wt) B100 (REG) 24.99 12.55 0.00 0.00 Agri-Pure 85 70.47 82.91 49.99 0.00 Agri-Pure 456 0.00 0.00 45.47 92.45 Priolube 1445 0.00 0.00 0.00 0.00 Priolube 3970 1.01 1.01 1.01 0.00 Priolube 3987 0.00 0.00 0.00 2.52 Viscoplex 10-310 0.51 0.59 0.54 0.25 Additin M 93.001 3.03 2.94 3.00 3.03 Functional V-508F 0.00 0.00 0.00 1.75 Total 100.00 100.00 100.00 100.00 Target ISO Viscosity Grade 22 32 46 68 Kinematic Viscosity @ 40° C., 21.99 30.23 46.75 66.74 cSt Kinematic Viscosity @ 100° C., 5.71 7.18 9.26 11.96 cSt Viscosity Index 222 215 185 178 Cloud Point (° C./° F.) −7.9/ −9.9/ −20.4/ −22.8/ 17.7 14.2 −4.7 −9.0 Pour Point (° C./° F.) −26.1/ −26.1/ −26.1/ −26.1/ −15.0 −15.0 −15.0 −15.0 Four Ball Wear, mm 0.61 0.39 0.35 0.37

Examples 5-7 used about 1% of Priolube 3970. For Example 8, about 2.5% of a higher viscosity synthetic ester, Priolube 3987, was used along with 1.75% of the high viscosity polymer Functional V-508F. As with the previous Examples 1-4, B100 was used only for the two lowest viscosity grades (Examples 5 and 6). It is noted that all of the Examples 5-8 achieved their targeted viscosity grade, including the ISO 68 blend (Example 8). This shows how a synthetic ester or a synthetic ester combined with a high viscosity polymer component can be used to boost the viscosity grade of a hydraulic fluid beyond what would be obtainable using only vegetable oil base oils. It should also be noted that to achieve the target ISO viscosity grades, the use of synthetic ester base oil in Examples 5-8 is clearly optional. This is easily seen by comparing Examples 1-3 with Examples 5-7. Regarding Example 8, if a higher level of the high viscosity polymer Functional V-508F was used, the use of the Priolube 3987 synthetic ester would not have been required, which may provide a cost benefit.

Once again, the inclusion of B100 in the ISO 22 and 32 viscosity grade hydraulic fluids (Examples 5 and 6) resulted in significantly higher VI compared to the ISO 46 and 68 hydraulic fluids (Examples 7 and 8) where B100 was not used. This further supports the conclusion that the addition of biodiesel contributes to a higher VI, making the use of biodiesel a particularly good blending component for hydraulic fluids where a lower ISO viscosity grade of 32 or 22 is needed.

In Examples 1-8, B100 has been used only in hydraulic fluid blends where the targeted viscosity grade is below ISO 46 and the use of B100 is needed to lower the viscosity of the other base oil(s) with which it is blended (i.e. Examples 1, 2, 5, and 6). However, B100 may also be used in hydraulic fluid compositions according to preferred embodiments of the invention where higher ISO viscosity grades are desired and use of biodiesel is not required. Also, the level of synthetic esters used in the previous examples has been mostly limited to only 1%, but higher levels may be used in conjunction with B100 and demonstrated in Examples 9-12. The composition and test data for these four blends are provided below in Table 5.

TABLE 5 B100 Used in Lower and Higher Viscosity Hydraulic Oil Blends Using Higher Levels of Synthetic Ester Base Oil Example Number 9 10 11 12 %(wt) B100 (REG) 22.86 9.47 2.29 10.32 Agri-Pure 85 71.60 84.93 49.23 85.02 Agri-Pure 456 0.00 0.00 42.94 0.00 Priolube 1445 0.00 0.00 0.00 1.05 Priolube 3970 2.01 2.01 0.00 0.00 Priolube 3987 0.00 0.00 2.01 0.00 Viscoplex 10-310 0.50 0.58 0.51 0.58 Additin M 93.001 3.03 3.01 3.02 3.03 Functional V-508F 0.00 0.00 0.00 0.00 Total 100.00 100.00 100.00 100.00 Target ISO Viscosity Grade 22 32 46 32 Kinematic Viscosity @ 40 C., 23.11 32.50 44.97 32.58 cSt Kinematic Viscosity @ 100 C., 5.92 7.41 8.97 7.52 cSt Viscosity Index 221 205 185 210 Cloud Point, C. −8 −11 −19 −10 Cloud Point, F. 17 13 −2 14 Pour Point, C. −26 −26 −26 −23 Pour Point, F. −15 −15 −15 −10

As can be seen, the composition for Example 9 is essentially the same as Example 5 except that about twice the synthetic ester is used. In order to maintain an ISO 22 viscosity grade, less B100 is used in Example 9 (22.86%) compared to Example 5 (24.99%). The same relationship exists between Example 10 (9.47% B100) and Example 6 (12.55% B100). Example 11 is similar to Example 7 in that both are ISO 46 blends. However, Example 7 did not use B100 whereas Example 11 does. Example 11 uses a higher viscosity synthetic ester (Priolube 3987) compared to what was used in Example 7 (Priolube 3970) so as to allow B100 to be incorporated into the blend and still achieve the target ISO 46 grade. Thus, by incorporating a sufficient amount of a sufficiently high viscosity base oil, B100 can be used in higher ISO viscosity grade hydraulic fluids. Example 12 is similar to Example 10 in that both are ISO 32 blends. However, Example 12 uses a synthetic ester (Priolube 1445) with an even higher viscosity than the synthetic ester used in Example 10 (Priolube 3970). This results in less B100 being needed in Example 10 to achieve the target ISO viscosity grade. Examples 10 and 12 demonstrate that there is more than one formulation approach that can be used to achieve a given lower ISO viscosity grade when B100 is used as a base oil.

The ISO 32 and 22 blends (Examples 9, 10, and 12) also have a higher VI than the ISO 46 blend (Example 11). The VI of Example 11 is the same as Example 7. This indicates that the ability of B100 to improve the VI of a hydraulic fluid is most evident in viscosity grades lower than ISO 46 where B100 is required. As previously discussed, a higher VI is more important in lower ISO viscosity grades. The ability of B100 to improve VI specifically in those lower ISO viscosity grades where its use is required to achieve the lower viscosity and where higher VI is most needed is an unexpected result.

Examples 13-15 were prepared to test the effect of B100 on the VI in hydraulic fluid compositions. Composition and test data for these three hydraulic fluid blends are provided below in Table 6. Previous Examples 7 and 8 are also included in Table 6 for ease of comparison.

TABLE 6 Effect of B100 on Viscosity Index of Hydraulic Fluid Blends Blend Number 7 13 8 14 15 %(wt) B100 (REG) 0.00 9.99 0.00 9.99 9.97 Agri-Pure 85 49.99 39.99 0.00 0.00 0.00 Agri-Pure 456 45.47 45.46 92.45 82.46 53.24 Priolube 1445 0.00 0.00 0.00 0.00 0.00 Priolube 3970 1.01 1.01 0.00 0.00 0.00 Priolube 3987 0.00 0.00 2.52 2.52 31.58 Viscoplex 10-310 0.54 0.54 0.25 0.23 0.22 Additin M 93.001 3.00 3.01 3.03 3.05 3.04 Functional V-508F 0.00 0.00 1.75 1.75 1.95 Total 100 100.00 100.00 100.00 100.00 Target ISO Viscosity 46 N/A 68 N/A 68 Grade Kinematic Viscosity @ 46.75 35.95 66.74 49.29 63.01 40° C., cSt Kinematic Viscosity @ 9.26 7.69 11.96 9.75 11.36 100° C., cSt Viscosity Index 185 191 178 188 176 Four Ball Wear, mm 0.35 0.37 0.37 0.37

Examples 13 and 14 are essentially Examples 7 and 8, respectively, with about 10% B100 added and a corresponding amount of the vegetable oil base oil removed. The viscosity grade of Example 7 is ISO 46 and of Example 8 is ISO 68. However, since the purpose of these examples was to determine the effect on VI resulting from the addition of B100 to a hydraulic fluid, no attempt was made to re-adjust the final blend viscosity of Examples 13 and 14 to correspond to Examples 7 and 8. Adding the 10% B100 to the compositions of Examples 13 and 14 resulted in a significant increase in VI compared to Examples 7 and 8, respectively. The increase in VI seen comparing Examples 7 and 8 with Examples 13 and 14 is not as much as what was seen in comparing earlier ISO 22 and 32 blends where B100 was used (Examples 1, 2, 5, and 6) with earlier ISO 46 and 68 blends where B100 was not used (Examples 3, 4, 7, and 8). However, this data does show that VI increases when adding B100 to a hydraulic fluid that originally did not contain B100.

Example 15 is similar to Example 14 except that the level of the synthetic ester is greatly increased while reducing the vegetable base oil by a corresponding amount. This example shows that much higher levels of a synthetic ester base oil can be used to make a higher ISO viscosity grade hydraulic fluid and still use B100 as a base oil.

Examples 16-18 were prepared to show that hydraulic fluids of differing ISO viscosity grades can be made where all the base oil is synthetic ester and B100 without any vegetable oil. Composition and test data for these three blends are provided below in Table 7.

TABLE 7 B100 Used in Hydraulic Fluid Blends Containing Synthetic Ester Base Oil without Vegetable Oil Blend Number 16 17 18 %(wt) B100 (REG) 0.00 37.36 5.24 Agri-Pure 85 0.00 0.00 0.00 Agri-Pure 456 0.00 0.00 0.00 Priolube 1445 0.00 59.09 91.23 Priolube 3970 96.43 0.00 0.00 Priolube 3987 0.00 0.00 0.00 Viscoplex 10-310 0.53 0.51 0.52 Additin M 93.001 3.04 3.04 3.02 Functional V-508F 0.00 0.00 0.00 Total 100.00 100.00 100.00 Target ISO Viscosity Grade 22 22 68 Kinematic Viscosity @ 40° C., cSt 22.28 22.68 64.78 Kinematic Viscosity @ 100° C., cSt 4.84 5.85 11.9 Viscosity Index 145 222 183

Example 16 is an ISO 22 hydraulic fluid where the base oil is entirely a low viscosity synthetic ester, Priolube 3970. Example 17 is also an ISO 22 hydraulic fluid, but uses a higher viscosity ester base fluid, Priolube 1445, and a significant amount of B100. The use of B100 in Example 17 results in a much higher VI than in Example 16, where no B100 was used. The VI of Example 17 is much higher than that of Example 16. Although it is possible to achieve an ISO 22 product using a very low viscosity synthetic ester base oil without needing to use any B100, it is also possible to achieve an ISO 22 product and achieve a much higher VI if a higher viscosity synthetic ester base oil is blended with B100 according to a preferred embodiment of the invention. The higher VI in the ISO 22 product resulting from the addition of B100 provides a significant performance advantage as a hydraulic fluid over an ISO 22 product with a lower VI, which is unexpected based on the prior art teachings. Example 18 is similar to Example 17, but uses much less B100 so as to provide an ISO 68 hydraulic fluid. The VI of Example 18 is lower than Example 17, but still significantly higher than Example 16 where no B100 is used and because Example 18 is an ISO 68 fluid, having a higher VI is not as important as it would be with an ISO 22 or ISO 32 fluid.

The previously described examples included only viscosity grades of ISO 22, 32, 46, and 68, as these are the most common ISO viscosity grades used in hydraulic equipment. The addition of biodiesel as a blending component base oil, along with at least one higher viscosity base oil (such as high viscosity synthetic esters, blown vegetable oil, polymers, or a combination thereof), may also be used for higher ISO viscosity grade hydraulic fluids and lubricants according to the invention.

Although primarily described herein with respect to use of biodiesel as a blending component in hydraulic fluid, according to other preferred embodiments of the invention, biodiesel may also be used with in other fluid lubricant areas, such as gear oils. As used herein, the term “vegetable oil” refers to any vegetable or plant oil suitable for use in a hydraulic fluid or lubricant, but specifically excluding blown vegetable oils, which are referred to herein specifically as “blown vegetable oil.” As used herein, the term “higher viscosity base oil” or “higher viscosity component” means any suitable base oil, other than a vegetable oil, that has a viscosity greater than ISO viscosity grade 46. As used herein, the term “environmentally acceptable” refers to any hydraulic fluid or lubricant that meets the criteria, standards, tests or other specifications set forth by the U.S. or any foreign government, any U.S. state government, any agency of any of those governments, any industry or manufacturing organization or association, ISO, and/or any educational institution to qualify for labeling or advertising as environmentally acceptable, environmentally friendly, environmentally considerate, or similar terminology indicating a reduced or minimal adverse environmental impact, including without limitation any of the specific standards referenced herein. Hydraulic fluids and lubricants according to preferred embodiments of the invention fall within an ISO viscosity grade of 22, 32, 46, 68, or higher, but may also include those fluids and lubricants made with biodiesel that fall within any range of viscosities greater than ISO grade 22. Unless otherwise specified, all percentages herein are by total weight of the final hydraulic fluid or lubricant composition. Those of ordinary skill in the art will appreciate upon reading this specification, including the examples contained herein, that modifications and alterations to the composition and methodology for making the composition may be made within the scope of the invention and it is intended that the scope of the invention disclosed herein be limited only by the broadest interpretation of the appended claims to which the inventor is legally entitled. 

What is claimed:
 1. A lubricant or hydraulic fluid comprising biodiesel and at least one other base oil.
 2. The lubricant or hydraulic fluid according to claim 1 wherein the lubricant or hydraulic fluid comprises around 0.1% to 55% by weight biodiesel.
 3. The lubricant or hydraulic fluid according to claim 1 wherein the lubricant or hydraulic fluid comprises around 0.1% to 45% by weight biodiesel and 99.9 to 55% total of one or more vegetable oils as the only other base oil.
 4. The lubricant or hydraulic fluid according to claim 3 wherein the lubricant or hydraulic fluid comprises around 1% to 40% by weight biodiesel and around 99% to 60% total of one or more vegetable oils.
 5. The lubricant or hydraulic fluid according to claim 3 wherein the lubricant or hydraulic fluid comprises around 5% to 35% by weight biodiesel and around 95% to 65% total of one or more vegetable oils.
 6. The lubricant or hydraulic fluid according to claim 1 wherein the lubricant or hydraulic fluid comprises around 0.1% to 55% by weight biodiesel and around 99.9% to 45% total of one or more higher viscosity base oils as the only other base oil.
 7. The lubricant or hydraulic fluid according to claim 6 wherein the lubricant or hydraulic fluid comprises around 5% to 55% by weight biodiesel and around 95% to 45% total of one or more higher viscosity base oils.
 8. The lubricant or hydraulic fluid according to claim 6 wherein the lubricant or hydraulic fluid comprises around 1% to 45% by weight biodiesel and around 99% to 55% total of one or more higher viscosity base oils.
 9. The lubricant or hydraulic fluid according to claim 6 wherein the lubricant or hydraulic fluid comprises around 5% to 40% by weight biodiesel and around 95% to 60% total of one or more higher viscosity base oils.
 10. The lubricant or hydraulic fluid according to claim 1 wherein the lubricant or hydraulic fluid comprises around 0.1% to 45% by weight biodiesel, around 89% to 53% total of one or more vegetable oils, and around 10% to 0.1 total of one or more higher viscosity base oils.
 11. The lubricant or hydraulic fluid according to claim 1 wherein the lubricant or hydraulic fluid comprises around 1% to 30% by weight biodiesel, around 90% to 69% total of one or more vegetable oils, and around 8% to 0.5% total of one or more higher viscosity base oils.
 12. The lubricant or hydraulic fluid according to claim 1 wherein the lubricant or hydraulic fluid comprises around 5% to 26% by weight biodiesel, around 95% to 73% total of one or more vegetable oils, and around 6% to 1 total of one or more higher viscosity base oils
 13. The lubricant or hydraulic fluid according to claim 1 wherein the lubricant or hydraulic fluid has an ISO grade of 22 or
 32. 14. The lubricant or hydraulic fluid according to claim 13 wherein the lubricant or hydraulic fluid has a Viscosity Index greater than
 200. 15. The lubricant or hydraulic fluid according to claim 1 wherein the other base oil comprises a vegetable oil, synthetic base oil, blown vegetable oil, a polymer, or a combination thereof.
 16. The lubricant or hydraulic fluid according to claim 1 wherein the lubricant or hydraulic fluid has an ISO grade of 46 or greater.
 17. The lubricant or hydraulic fluid according to claim 1 wherein the other base oil comprises one or more vegetable oils and no synthetic base oils.
 18. The lubricant or hydraulic fluid according to claim 1 wherein the other base oil comprises one or more synthetic base oils and no vegetable base oils.
 19. The lubricant or hydraulic fluid according to claim 18 wherein the synthetic base oils are synthetic esters, oil-soluble polyalkylene glycols, or a combination thereof.
 20. The lubricant or hydraulic fluid according to claim 1 wherein the lubricant or hydraulic fluid meets one or more standards or specifications as environmentally acceptable.
 21. A method of efficiently transferring hydraulic power using a hydraulic fluid comprising biodiesel and at least one other base oil.
 22. The method according to claim 21 wherein the hydraulic fluid comprises around 0.1 to 55% biodiesel.
 23. The method according to claim 21 wherein the hydraulic fluid comprises around 1 to 30% by weight biodiesel.
 24. The method according to claim 21 wherein the hydraulic fluid comprises around 5 to 26% by weight biodiesel.
 25. The method according to claim 21 wherein the hydraulic fluid has an ISO grade of 22 or
 32. 26. The method according to claim 25 wherein the hydraulic fluid has a Viscosity Index greater than
 200. 27. The method according to claim 21 wherein the lubricant or hydraulic fluid meets one or more standards or specifications as environmentally acceptable.
 28. A method of making a lubricant or hydraulic fluid comprising mixing around 0.1 to 45% biodiesel with another base oil, wherein the percentage is by weight of the final lubricant or hydraulic fluid.
 29. The method according to claim 28 wherein the lubricant or hydraulic fluid has an ISO grade of 22 or
 32. 30. The method according to claim 29 wherein the lubricant or hydraulic fluid has a Viscosity Index greater than
 200. 31. The method according to claim 28 wherein the other base oil comprises one or more vegetable oils and no synthetic base oils.
 32. The method according to claim 28 wherein the other base oil comprises one or more synthetic base oils and no vegetable base oils.
 33. The method according to claim 32 wherein the synthetic base oils are synthetic esters, oil-soluble polyalkylene glycols, or a combination thereof.
 34. The method according to claim 28 wherein the lubricant or hydraulic fluid meets one or more standards or specifications as environmentally acceptable.
 35. The method according to claim 28 further comprising mixing one or more performance additives with the biodiesel and base oil.
 36. The method according to claim 35 wherein the total amount of performance additive or additives is around 0.1 to 15% by total weight of the lubricant or hydraulic fluid. 